Many vehicles include a rear closure in the form of a tailgate for accessing a cargo area within a vehicle's cabin. Typically, such a cargo area is disposed behind rear seats in the vehicle cabin (e.g., behind a second or third row of seats in the vehicle cabin). The tailgate for this cargo area conventionally includes a steel frame that is pivotally secured to the vehicle body and/or vehicle frame so as to be pivotable between a closed position and an open position. For example, the tailgate may be pivotable along an upper edge thereof so as to be movable between a closed position and a flip-open position. Often, a tailgate liner is secured to the steel frame along an inner side of the steel frame to form an interior surface of the vehicle. In addition, a tailgate skin can be secured to the steel frame on an outer surface of the tailgate to form an exterior surface of the vehicle. Thus, the tailgate liner faces inward into the vehicle cabin when the tailgate is in a closed position and the tailgate skin faces outward. One function of the tailgate liner is to improve aesthetics of the vehicle as without the tailgate liner the tailgate frame might appear unsightly.
In addition to forming an inside surface for the vehicle, some tailgate liners also cover an underside of the tailgate that may only be viewable when the tailgate is in the open position. Often, several tailgate parts, features and/or operating devices are provided along the underside of the tailgate. For example, these can include latching and/or locking mechanisms for securing the tailgate in the closed position, buttons or switches for operating powered tailgates (e.g., a close tailgate button that, when depressed, actuates automated powered closure of the tailgate), handles or other grasping assemblies, etc. On higher end vehicles, it may be desirable to present the underside of the tailgate in an aesthetically pleasing manner and therefore not overly expose the underside of the tailgate (e.g., the tailgate frame) to provide an improved appearance or look for the tailgate.
Conventional tailgate linings are often made by standard injection molding processes. Integrally molded features can typically be incorporated into the underside of the tailgate lining via complicated die assemblies in the injection molding tool (e.g., cavity slides) and/or complicated molding techniques. However, as new materials have been developed for vehicle parts that provide various enhanced structural properties (e.g., weight savings), sometimes the conventional injection molding techniques are not suitable for use with such new materials.